Re: fw_devlink breakage on SDM845 / a630 with DSI displays

From: Saravana Kannan <saravanak@google.com>
To: Rob Clark <robdclark@gmail.com>
Cc: Caleb Connolly <caleb@connolly.tech>,
	John Stultz <john.stultz@linaro.org>,
	Amit Pundir <amit.pundir@linaro.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Douglas Anderson <dianders@chromium.org>,
	Stephen Boyd <swboyd@chromium.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>
Subject: Re: fw_devlink breakage on SDM845 / a630 with DSI displays
Date: Wed, 19 May 2021 14:52:53 -0700	[thread overview]
Message-ID: <CAGETcx-2TySe=w1qAbtj2AJu6fNo_gaYnyP6GN150ShT1TvDfA@mail.gmail.com> (raw)
In-Reply-To: <CAF6AEGvnL9mOp3vKuSvz=KDijtFVMdKCF4BXSLxXeoR38O-SUg@mail.gmail.com>

On Wed, May 19, 2021 at 8:36 AM Rob Clark <robdclark@gmail.com> wrote:
>
> + some more folks and msm list..
>
> I suppose I didn't hit this because CONFIG_FBDEV_EMULATION is not
> normally enabled for CrOS.. but I'm not really to familiar with
> fw_devlink
>
> BR,
> -R
>
> On Wed, May 19, 2021 at 8:26 AM Caleb Connolly <caleb@connolly.tech> wrote:
> >
> >
> > Hi,
> >
> > Since -rc1 I've been hit by some DRM breakage in freedreno which happens
> > when fw_devlink=on. It seems to cause some clocks (rcg) to get stuck and
> > break DSI displays, here's a full log from the OnePlus 6:
> > https://paste.ubuntu.com/p/8kPx4nFGF5/ (that is with
> > "deferred_probe_timeout") The PocoPhone F1 also seems to be affected by
> > this.
> >
> > The display will still come up after pressing the power button a few
> > times, although it will be incredibly slow.
> >
> > It's worth noting that the issue only happens with
> > CONFIG_FBDEV_EMULATION is enabled, I've previously required this to see
> > kernel logs during boot and general boot splash with postmarketOS.
> > Without it the display will be stuck on the bootloader splash until I
> > press the power button and cause it to update once UI (like Phosh) has
> > started (though this has been the case for quite some time).
> >
> > I'd appreciate any help with debugging / resolving this issue, I'm
> > afraid I haven't been able to determine much from some brief digging.
> >

Hi Caleb,

Is this a device that's supported upstream? If so, can you please
point me to the DTS file that corresponds to this board?

Also, can you please change all the dev_dbg to dev_info in these
functions and give me the full boot log?
device_link_add()
device_links_check_suppliers()

Can you also tell what device are not probing with fw_devlink=on that
might be probing with fw_devlink=permissive?
You should be able to compare /<debugfs>/devices_deferred to figure that out.

Thanks,
Saravana